Yeah sorry. If I bought the game and I have some left over money to buy in game currency then I will buy some because guess what? It's my game that I bought with my hard earned money and if I wanna use my hard-earned money for more in game stuff then I will and I will feel no shame about it
The excuse "I bought the game and I'll do what I want with it" is really old and as much as it may sound true, it isn't always the case. It's like saying "I paid for my car, I'll drive as fast as I want". Unfortunately Nintendo has the right to say how we should play our games or use our Switch, which is why they reserve the right to patch exploits and ban exploiters and hackers.